This invention relates to an effective technology concerning a format for forwarding data to portable electronic equipment housing a microcomputer and further, a format for loading an application program of portable electronic equipment, which can be used for example for an MP3 player for playing audio data compressed in compliance with standards like MPEG 1 layer III, a portable information terminal or game equipment.
Portable electronic equipment like an MP 3 player, a portable information terminal or game equipment for example, houses a microcomputer (including what would be called a microprocessor). A variety of functionalities are realized through controlling a program of this microcomputer. Further, among such electronic equipment are types of equipment which realize multifaceted functionalities through housing multiple programs or through being able to have programs changed.
Normally, a portable information terminal is configured for connection to a stationary host information processing apparatus like a personal computer (hereinafter xe2x80x9cPCxe2x80x9d) enabling exchange of information and usually, such a portable information terminal can be used by being carried separately after being detached from a host information processing apparatus once data has been conveyed from the host information processing apparatus to the portable information terminal and stored therein.
FIG. 11 shows a configuration of a portable information terminal having such function, proposed by the present inventors and not known herebefore. Numeral 100 in that drawing represents a portable information terminal and 200 represents a host information processing apparatus, the apparatuses including transmission/reception sections 105 and 205 for data transfer by serial transfer via cable 300, respectively.
Microcomputer (hereinafter xe2x80x9cCPUxe2x80x9d) 101, non-volatile memory 102 like mask ROM (Read Only Memory) or flash memory, volatile memory 103 like RAM (Random Access Memory) and peripheral device 104 like an LCD controller controlling display of a liquid crystal panel may be included in portable information terminal 100. Non-volatile memory 102 is not rewritable, however because contents stored therein are not deleted when there is no power being supplied, a program like an OS (operating system) run by CPU 101 stored in non-volatile memory 102 is run by CPU 101 from the initial state immediately after power input.
When conveying data from host information processing apparatus 200 to portable information terminal 100, a connection like cable 300 is made between them and data can be sent and received through their respective transmission/reception sections 105 and 205 in conformance with a transmission interface like RS-232C (Recommended Standard 232C interface standard), USB (Universal Serial Bus interface standard), IEEE1394 (interface standard) IrDA (an interface standard of the Infrared Data Association). Data delivered to portable information terminal 100 is stored in volatile memory 103.
Non-volatile memory 102 for program storage is required for a conventional portable information terminal 100 described above in addition to volatile memory 103 for data storage. Because with existing semiconductor production technology the price of non-volatile memory like flash memory is relatively high in comparison to volatile memory like DRAM the cost of a system utilizing non-volatile memory is high. Further the number of parts increases if non-volatile memory is necessary in addition to volatile memory, and the system mounting space required increases. This creates a problem in dealing with a number of factors which mitigate against realizing small size and lightweight.
An object of this invention is to provide a portable information terminal the cost of which can be lower.
An other object of this invention is to provide a portable information terminal which can be smaller and lighter.
Another object of this invention is to provide a portable information terminal for which the time required on a production and/or assembly line can be reduced.
The above and further objects and features of the invention will more fully be apparent from the following detailed description with accompanying drawings.
Hereunder is a description of various aspects of the invention as disclosed in this application.
According to a first aspect of this invention, in addition to doing away with non-volatile memory of a portable information terminal, the configuration is such that a portable information terminal and host information processing apparatus can connect via a bus and a program executed by a CPU of the portable information terminal is sent from a host information processing apparatus on the bus to the portable information terminal for storage in volatile memory.
More specifically, the present invention provides an information processing system comprising:
portable electronic equipment including a first microcomputer, a first volatile memory, a first bus connecting the first microcomputer and volatile memory and a first bus connection means for connecting the first bus to a bus of an external device; and
an information processing apparatus including a second microcomputer, a second volatile memory, a non-volatile memory, a second bus connecting the second microcomputer, a second volatile memory and a non-volatile memory and a second bus connection means for connecting the second bus to a bus of another external device;
wherein the portable electronic equipment is provided with a bus disconnection means enabling disconnection of the connection between the second microcomputer and the second bus so that when there is a connection through the first and second bus connection means between the first bus of the information processing apparatus and the second bus of the portable electronic equipment, the microcomputer and the bus is disconnected by the bus disconnection means.
Accordingly, the microcomputer of the information processing apparatus is able to access the volatile memory of the portable electronic equipment via the connected bus, rendering a transmission means unnecessary and enabling cost reductions while data transfer from the information processing apparatus to the portable electronic equipment becomes faster. Further, because there is no non-volatile memory for the portable electronic equipment substantial cost reductions for the portable electronic equipment are enabled and equipment can be smaller and lighter.
It is desirable that connection detection means is further provided for said information processing apparatus for detecting connection between the information processing apparatus and the portable electronic equipment and the configuration is such that, based on detection signals output from the connection detection means, the second bus connection means of the information processing apparatus and the first bus connection means of the portable electronic equipment are activated for mutual connection of the second and first buses.
The system is configured such that the bus disconnection means disconnects the connection between the first microcomputer of the portable electronic equipment and the first bus based on the detection signals output from the connection detection means.
According to another aspect of this invention, a connection detection means is further provided for each of the information processing apparatus and the portable electronic equipment for detecting connection between the information processing apparatus and the portable electronic equipment, and the configuration is such that based on detection signals output from these connection detection means, the second bus connection means of the information processing apparatus and the first bus connection means of the portable electronic equipment are each activated for mutual connection of the second and first buses. This makes it unnecessary to deliver a signal controlling the bus connection means from the information processing apparatus to the portable electronic equipment, enabling a reduction in the number of transmission lines.
According to another aspect of this invention, a power on reset circuit for detecting startup of power voltage input and generating a reset signal is further provided for the portable electronic equipment, the configuration being such that, when a connection between the information processing apparatus and portable electronic equipment is cut, a reset signal is generated from the power on reset circuit and the first microcomputer of the portable electronic equipment is reset through that reset signal. This avoids the microcomputer of the portable electronic equipment hanging up after a connection between the information processing apparatus and portable electronic equipment is disconnected.
According to another aspect of this invention, when the information processing apparatus and the portable electronic equipment are connected, at least a boot program of the portable electronic equipment is transmitted via the first and second buses from the information processing equipment to the first volatile memory of the portable electronic equipment and stored therein, and when the information processing apparatus and the portable electronic equipment are disconnected from each other, the first microcomputer of the portable electronic equipment is reset through a reset signal generated by the power on reset circuit so that the first microcomputer executes a boot program stored in the first volatile memory. Accordingly, in addition to obviating the necessity for non-volatile memory for storing a boot program of portable electronic equipment, normal control of internal parts of such equipment is enabled even without that kind of memory. Because processes at the production and/or assembly line for storing a boot program in non-volatile memory are thereby rendered unnecessary, it becomes possible to substantially reduce the time required for completion of a product.
According to another aspect of this invention, a second signal conversion circuit for converting a first signal on the second bus of the information processing apparatus into a second signal is further provided in the information processing apparatus, the second signal having a number of bits smaller than that of the first signal. This enables the number of signal lines connecting an information processing apparatus and portable electronic equipment to be reduced, a reduction in size of connectors enabling the size of a device itself to be reduced.
According to another aspect of this invention, the information processing apparatus is further provided with a means for display for making displays based on a detection signal output from the connection detection means. Through this, it becomes possible for a user to easily confirm that a connection from information processing equipment to portable electronic equipment must not be disconnected, thereby avoiding problems of portable electronic equipment being disconnected from information processing equipment during data transfer with data loss or a system hangup resulting subsequently.